Questions about CRT Safety Glass

[Nigel Goodwin]

By then, the Japanese manufacturing had already upgraded to turbomolecular pumps, and was anecdotally told that they had 20X lower vacuum. One of the several reasons that those tubes lasted so long.

Perhaps you might find this interesting?.

At one particular time Grundig had a very high failure rate on the Toshiba CRT's fitted in a particular 20 inch model.

Following an extensive investigation it turned out that the guns were stored in a room at the factory, and that room (like most) had a suspended tile ceiling.

The outer roof of the factory developed a leak, and it rained in, and water settled on the ceiling tiles of the room containing the electron guns. This increased the humidity in the room, and contaminated the electron guns. When the CRT's were manufactured they initially worked perfectly fine, but after about 6-9 months there were massive low emission failures. The sets were still under warranty, and Grundig replaced the CRT's - and I presume Toshiba covered the cost?. A few did manage to last past the 12 month warranty, but fairly obviously Grundig covered any of those that fell within the faulty serial number range.

There was mention above of 32 inch CRT's, there were obviously also 36 inch ones - plus Toshiba made a 39 inch 4:3 CRT, and we sold a number of such models from Grundig - they were seriously heavy, and came with detachable metal handles at each side so you could carry them (two man lift - and two STRONG men at that). Never had occasion to smash one of those CRT's, I bet they would have gone with a good bang

 

[schmitt trigger]

Storing the bare gun assemblies? That was a big no-no in our place. The different gun types were produced at most a couple of days before actual tube assembly.
During the Christmas shutdown any unused gun assemblies were vacuum sealed in a bag. The glass envelopes were purged with dry nitrogen and sealed. But any product which had already the gun attached to the glass envelope had to be completed.

Not all Japanese manufacturers were equivalent.
The best was Sony, followed by Matsushita’s top tier brands.

Never had any personal experience with Toshiba, but do recall there were less expensive.

 

[unclejed613]

Could it have been built into the front layer of the tube? Just asking because apart from my old RCA, I haven't seen any with safety glass.

i replaced a lot of PC monitor CRTs, and the front glass is "welded " to the bell section, and the front glass is very thick compared to older CRTs. last year i saw a video on youtube about a company in the USA that rebuilds CRTs, and shows the whole process.

 

[unclejed613]

Not all Japanese manufacturers were equivalent.

Mitsubishi CRTs had the best red phosphor... real red instead of the slightly orange tint of most others...

 

[RayRay1132]

Mitsubishi CRTs had the best red phosphor... real red instead of the slightly orange tint of most others...

I love the red and pure green phosphor crts, something about them is just oddly satisfying.